Viroids can cause diseases of considerable economic importance; in Europe the main concern is with pospiviroids that may affect the tomato and potato industries. Methods for detection are required that are both sensitive and robust. The detection method described here is a probe hybridization method with a commercially available digoxigenin (DIG) labelled full-length Potato spindle tuber viroid (PSTVd) RNA probe. This method detects PSTVd and all other known pospiviroids.